Spatio-Temporal Distribution of Supra-Glacial Ponds and Ice Cliffs on Verde Glacier, Chile

Abstract

Known for their important role in locally enhancing surface melt, supraglacial ponds and ice cliffs are common features on debris-covered glaciers. We use high resolution satellite imagery to describe pond-cliff systems and surface velocity on Verde debris-covered glacier, Monte Tronador, and Southern Chile. Ponds and ice cliffs represent up to 0.4 and 2.7% of the glacier debris-covered area, respectively. Through the analyzed period and the available data, we found a seasonality in the number of detected ponds, with larger number of ponds at the beginning of the ablation season and less at the end of it. Using feature tracking, we determined glacier surface velocity, finding values up to 55 m/yr on the upper part of the debris-covered area, and decreasing almost to stagnation in the terminus. We found that larger ponds develop in glacier zones of low velocity, while zones of high velocity only contain smaller features. Meanwhile, ice cliffs appeared to be less controlled by surface velocity and gradient. Persistent ice cliffs were detected between 2009 and 2019 and backwasting up to 24 m/yr was measured, highlighting significant local glacier wastage.

Controls on Ice Cliff Distribution and Characteristics on Debris‐Covered Glaciers

“…While models accurately simulate the energy and mass balance contribution of individual ice cliffs (Buri et al., 2016; Kneib et al., 2022), their application at large spatial scales is limited by our understanding of the controls of ice cliff distribution. Indeed, estimates of ice cliff density are difficult to make (Anderson, Armstrong, Anderson, & Buri, 2021; Herreid & Pellicciotti, 2018; Kneib et al., 2020) and vary widely in time and space, between 1% and 15% of the debris‐covered area (e.g., Falaschi et al., 2021; Kneib et al., 2021; Loriaux & Ruiz, 2021; Sato et al., 2021; Steiner et al., 2019; Watson, Quincey, Smith, et al., 2017). Remote sensing studies have shown that cliffs are often associated with ponds (Steiner et al., 2019; Watson, Quincey, Carrivick, & Smith, 2017), hinting at a preferential location of ice cliffs where lower glacier longitudinal gradient and surface velocities promote surface ponding (Bolch et al., 2008; Quincey & Glasser, 2009; Quincey et al., 2007; Racoviteanu et al., 2021; Reynolds, 2000; Sakai & Fujita, 2010; Salerno et al., 2012).…”

Quantifying Supraglacial Debris‐Related Melt‐Altering Effects on the Djankuat Glacier, Caucasus, Russian Federation

“…The most important of these processes include within‐debris convection, meltwater pooling, within‐debris refreezing of meltwater, within‐debris water retention, as well as the presence of ice slopes and cliffs (Petersen et al., 2022; Reid & Brock, 2010). The presence of supraglacial water bodies, bare‐ice slopes and ice cliffs has been shown to potentially increase local melt rates substantially and act as local ablation hotspots (Buri et al., 2021; Loriaux & Ruiz, 2021; Miles et al., 2022). To capture such small‐scaled and detailed processes, however, high resolution input data are required at both temporal and spatial scales, which is out of scope for this study.…”

Steep ice – progress and future challenges in research on ice cliffs

“…Their aspect can vary widely within a single cliff and between different cliffs on a single glacier (Steiner and others, 2019). Ice cliffs cover , 15% of the area of the debris-covered tongue of glaciers (Steiner and others, 2019;Anderson and others, 2021;Kneib and others, 2021a;Loriaux and Ruiz, 2021). Their genesis has been hypothesized to be related to spatially heterogeneous debris thicknesses leading to differential melt and debris mobilization (Nicholson and others, 2018;Moore, 2021), subglacial streams or ponds leading to debris remobilization and undercutting (Sakai and others, 2000;Mölg and others, 2019), collapsing englacial channels (Benn and others, 2012;Reid and Brock, 2014) or crevasses (Reid and Brock, 2014;Steiner and others, 2019).…”

“…Complex models have only been applied in recent years (Buri and others, 2016b), along with the investigation of their distribution beyond the glacier scale (Steiner and others, 2019;Kneib and others, 2021a). More recently, they have also been described in the Alps (Reid and Brock, 2014), Andes (Loriaux and Ruiz, 2021) and Alaska Range (Anderson and others, 2021).…”